Journal of experimental zoology . a§ ••. Fig. 39. Axial section of an unfertilized egg that had stood in the sea-water two hoursand seven minutes before killing. The a and c spherules of the endoplasm have segregated out{, and ; compare Fig. 5). A clear layer has arisen between the ectoplasm (£) and thea endoplasm; the outer centrosome of the maturation spindle has divided once, and the inner oneserveral times. 32 and 40). Sections taken at this time show that part of thepolar ectoplasm plunges into the interior of the egg (Fig. 40, ).This is very conspicuous in the four-celled stag
Journal of experimental zoology . a§ ••. Fig. 39. Axial section of an unfertilized egg that had stood in the sea-water two hoursand seven minutes before killing. The a and c spherules of the endoplasm have segregated out{, and ; compare Fig. 5). A clear layer has arisen between the ectoplasm (£) and thea endoplasm; the outer centrosome of the maturation spindle has divided once, and the inner oneserveral times. 32 and 40). Sections taken at this time show that part of thepolar ectoplasm plunges into the interior of the egg (Fig. 40, ).This is very conspicuous in the four-celled stage containing thespindles for the next division. A tongue of endoplasm thenextends across, severing the portion lying internally from theportion that remains superficial in position (Fig. 40). It is possi- Elementary Phenomena of Embryonic Developinent 209 ble that the upflow of the polar ectoplasm may carry some of itabove the line of the next cleavage furrow, so that a certain amountmay go into id. An upflow of endoplasmic spherules g
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1904
